Is this the sixth mass extinction on Earth? Fears could be exaggerated.

Earth is about to experience its sixth major extinction, according to headlines for years. Human activity, according to many experts, has accelerated the extinction of species to levels not seen since the extinction of the dinosaurs.

However, a recent study from the University of Arizona casts doubt on that theory, indicating that the crisis might not be developing as quickly as many believe.

The study found that plant, arthropod, and land vertebrate extinctions actually peaked over a century ago and have been dropping ever since. The discovery presents a more nuanced picture of biodiversity loss, one in which the most terrible forecasts may be unrealistic.

Examining extinction data in more detail

In addition to closely examining 912 species that went extinct over the last 500 years, the researchers analysed data from almost two million species.

The majority of those losses, the researchers discovered, happened to island-dwelling species, especially vertebrates and molluscs, frequently as a result of human-introduced invasive species.

Native species that had developed without such predators were wiped out when rats, pigs, and goats were introduced to islands like Hawaii. Kristen Saban and John Wiens from the University of Arizona's Department of Ecology and Evolutionary Biology carried out the study.

According to Wiens, "we found that the causes of those recent extinctions were very different from the threats species are currently facing." Because the factors are changing quickly, especially with regard to habitat loss and climate change, it is difficult to generalise these historical extinction patterns into the future.

Extinctions in the past are not accurate indicators.

The study contends that numerous extinctions in the past cannot accurately forecast current events. Invasive species on islands have been the main offenders throughout the last 500 years. These days, habitat destruction on continents is the main issue.

Entire groups of species are driven to the brink when freshwater habitats are contaminated and forests are removed. The team was somewhat aback by how poorly historical extinction patterns anticipated current threats, according to Saban.

"We are surprised to find that historical extinctions are poor and unreliable indicators of the current threat that any particular group of plants or animals is facing," she stated.

The rates of extinction differ greatly.

According to the study, extinction rates differed greatly amongst categories, with plants and arthropods suffering lower losses overall, while molluscs and vertebrates were most severely impacted.

Invasive species were a major factor in the extinction of local biodiversity on islands. However, the greatest hazard on continents was habitat loss. Additionally, freshwater environments have been especially susceptible to human influences, according to the study.

Climate change's role

The fact that climate change hasn't yet been a significant documented cause of extinction was one of the study's more surprising conclusions.

According to Wiens, "that does not mean that climate change is not a threat." "It simply means that threats that exist today and in the future are not reflected in past extinctions."

The time lag between climatic change and species decrease may be the cause of the lack of conclusive data on climate-driven extinctions. It's possible that the full consequences of global warming have not yet materialised.

The researchers looked at conservation statuses for over 163,000 species as categorised by the International Union for Conservation of Nature (IUCN) in order to assess ongoing dangers.

According to Wiens, "the current threat level provides probably our best hint of what is currently happening and might happen in the near future."

We discovered that the patterns of current threats differ from those of previous extinctions. For instance, the most vulnerable species nowadays are those on the mainland that are experiencing habitat damage, but the majority of extinct species are vertebrates and molluscs on islands that were wiped out by invasive species.

Hope is provided by declining extinction rates.

The investigation revealed no proof that extinction rates are accelerating, despite popular perception. According to Wiens, "we demonstrate that extinction rates peaked many decades ago rather than accelerating towards the present as many people claim."

According to Wiens, extinction rates for land vertebrates, plants, and arthropods have actually decreased since the early 20th century.

He continued by saying that the fact that so many people are working hard to prevent the extinction of species is one of the reasons why extinction rates are decreasing. "And we have proof from other studies that funding conservation efforts is effective."

The crisis is still ongoing.

The study shouldn't be interpreted as downplaying the biodiversity threat, Saban stressed. "I believe we have not yet seen the kinds of effects that biodiversity loss might have, and it is a huge problem right now," she stated.

"But it's crucial that we discuss it accurately and that our science is rigorous in how we're able to describe these losses and stop future ones." By avoiding the alarming language that frequently permeates extinction conversations, The researchers want to promote more sophisticated, data-driven strategies for preserving life on Earth.

"The problem becomes insurmountable if we're saying that what is happening right now is like an asteroid hitting Earth," Saban stated.

"We hope that by analysing the data in this way, our study helps inform our overall understanding of biodiversity loss and how we can come up with better ways to address it."